DE102014111683A1 - Press drive for a forming device - Google Patents

Abstract

The invention relates to a press drive for a forming device comprising a central drive shaft with an eccentric guide unit, a toggle mechanism with two toggle levers, each having a first and a second pivotally interconnected lever arm. In order to provide an improved press drive with which forming work can be carried out particularly accurately and efficiently, it is provided that the first lever arms with the eccentric guide unit and the second lever arms are each connected to at least one plunger connection with a press ram.

Description

The invention relates to a press drive for a forming device for machining workpieces with a central drive shaft and a toggle mechanism with two toggle levers, each having at least one plunger connection with a press ram.

Devices for forming workpieces, in particular, for example, sheets, are known. For example, the DE 10 2012 102 527 A1 a press which can move a press ram up and down by means of an eccentric drive and a toggle mechanism. Due to the fact that the demands on the workpieces to be processed continue to rise, however, there is a high demand for forming devices that allow a particularly high forming quality. For this it is necessary that the leadership of the press ram and the power transmission of the respective drive units are further improved on the press ram. In particular, tilting movements of the press ram are to be prevented even with particularly high strokes.

Another important aspect of modern forming equipment is their increase in efficiency to lower both the operating costs and the unit cost of the workpieces produced on the press.

The invention has for its object to provide an improved press drive, with the forming work can be carried out particularly accurately and efficiently.

The invention is based on the idea that a particularly precise guidance of the press ram is possible, provided that the power transmission of the drive unit takes place with a plurality of synchronously acting on the press ram connections between the drive unit and the press ram. In this case, the press ram should have at least two evenly distributed plunger joints with the drive unit to prevent tilting of the press ram and to allow a uniform stroke of the press ram. In addition, the force on all ram connections must be as synchronous as possible.

By arranging only a single drive shaft and the uniform distribution of the acting force over two toggle lever on at least two plunger connections, the inventive device allows precise guidance of the press ram.

In this case, due to the coupling of the two toggle lever on the eccentric guide unit, the driving force is transmitted by an opposite movement to the toggle lever, whereby cancel the forces on the drive shaft almost mutually. In addition, it is achieved by the single central drive shaft with the associated toggle mechanism, that the stroke of the press ram can be made particularly large and a particularly low torque acts on the drive shaft during the press cycle, which in turn reduces the energy consumption of the press is further reduced.

A forming device is understood to mean a machine, in particular a press, with which conventional production methods, such as pressing, bending, drawing, drawing, punching and / or cutting, can be carried out on workpieces. Accordingly, the terms used such as presses, press ram, press drive, press frame, press stroke, press size, press pressure u. Ä. Not restrictive to understand pressing method, but of course include all other feasible with such a machine manufacturing process.

The drive of the drive shaft is in particular electrically. For example, a conventional electric drive can be used. Advantageously, however, the forming device is designed as a servo press with a servomotor, in particular a torque motor. In this way, a particularly high torque can be applied to the drive shaft, whereby high forces act on the press ram. Thus, the inventive press can be designed in particular to operate with pressing pressures of between 100 and 3500 t, preferably with pressing pressures in the range of between 400 and 2500 t.

In particular, in the arrangement of particularly strong drive units or even more acting on the drive shaft drive units, it is also possible, for example. Between the drive shaft and the drive unit to arrange a transmission.

Under the eccentric guide unit are in particular arranged on the drive shaft, with the first lever arms in connection, connecting elements to understand, by means of which the power transmission from the drive shaft to the knee lever. The connecting elements are eccentric, i. arranged eccentrically on the drive shaft.

The toggle mechanism transmits the force provided by the drive shaft to the press ram and thus establishes the connection between the drive shaft and the press ram. The two toggle levers are arranged in particular mirror-symmetrically about a central axis. In this case, under the central axis in particular one to the Rotary axis of the drive shaft (hereinafter drive axis direction) perpendicular longitudinal axis to be understood.

The toggle mechanism has a two-point tappet connection that allows safe and accurate guidance of the press ram. That is, the toggle mechanism is connected to the press ram via two connecting portions (ram connections). The plunger connections can be arranged mirror-symmetrically in accordance with the knee levers and extend, for example, over as wide a section as possible of the press ram.

In particular, however, the toggle mechanism is connected via a four-point tappet connection with the press ram, so that according to a development of the invention, each second lever arm has at least two plunger connections with the press ram, whereby a particularly secure and precise guidance of the press ram is made possible.

The plunger connections can be arranged next to one another and in particular spaced from one another on the second lever arms of the toggle lever in the drive axis direction. Accordingly, the second lever arms can extend in the drive axis direction in a particularly wide manner, for example over the plunger width, so that the two plunger connections on the second lever arms are particularly widely spaced from each other. As a result, a particularly secure guidance of the press ram is achieved.

If, for example, the forces to be transmitted to the press ram are particularly high, each second lever arm can also have more than two ram connections to the press ram so that, for example, a six-point ram connection between the toggle mechanism and the press ram can be present.

Regardless of the number of plunger connections, a separate guide device can additionally be arranged between the press ram and the press frame.

The bearing of the toggle lever in the press drive can be done differently. However, particularly preferably, the toggle levers are each rotatably mounted about a central bearing axis arranged in the first lever arm. The bearing axis is preferably arranged stationary on a press housing. Due to the arrangement in the first lever arm, a particularly large stroke of the press ram, i. a particularly large distance between a press table and the press ram can be achieved.

The two lever arms are articulated, for example. By means of a rotary joint, connected to each other. It is provided according to a development of the invention that the first lever arm and / or the second lever arm has at least two parallel juxtaposed Hebelarmkörper.

For example, the first lever arm can consist of two lever arm bodies arranged parallel to one another and spaced apart from one another. The two Hebelarmkörper can be identical and arranged side by side in the drive axis direction.

In this case, each first lever arm body forms an articulated connection with the second lever arm. The two first lever arm bodies may, for example, be arranged in a central position of the second lever arm, but are preferably arranged in each case on the outer sides of the second lever arm.

Of course, a reverse training is possible in which the second lever arm has two lever arm body and the first lever arm only one Hebelarmkörper. Also, the first and second Hebelarmkörper can each consist of two or each a Hebelarmkörper. By forming one or both of the lever arms of two parallel juxtaposed Hebelarmkörpern, a particularly good and uniform power transmission from the drive shaft via the toggle mechanism on the press ram is possible.

For transmitting the driving force from the drive shaft to the toggle is provided according to a development of the invention that the eccentric guide comprises a push rod which is mounted with a first end in a lever guide on the first lever arm.

The push rod transmits the rotational forces of the drive shaft to the first lever arm of the toggle lever. For this purpose, the push rod is rotatably mounted with a first end opposite the first end of the eccentric guide unit. According to the arrangement of two toggle levers and at least two push rods are arranged, each push rod connects the eccentric guide unit with one of the toggle lever. The push rods are arranged on the eccentric guide unit such that the drive of the push rods takes place in opposite directions. Thus, for example, the push rod connected to the first toggle lever is, for example, moved upward while the push rod connected to the second toggle lever is moved downwards. However, the push rods are arranged such that they always move in the same direction about the drive shaft.

The bearing of the push rod on the first lever arm takes place in a Hebelarmführung, in which the first end of the push rod between two Positions back and forth is movable. The Hebelarmführung is in particular designed as a sliding guide, in which, for example, on the push rod, a sliding shoe is arranged, which is mounted in a sliding guide element in the lever arm.

The movement of the first end of the push rod in the lever arm takes place in particular along a longitudinal axis direction of the lever arm. Depending on the number of lever arm body can, for example, be arranged for each lever arm body, a push rod. In particular, however, regardless of the number of Hebelarmkörper a lever arm, a push rod is arranged, which is connected with its first end to a connecting axis, wherein the connecting axis extends, for example. By a plurality of juxtaposed Hebelarmkörper and is mounted in each Hebelarmkörper with a Hebelarmführung.

For a particularly secure guidance of the press ram is provided according to a development of the invention that the push rod is mounted with its first end in a stand guide.

The storage of the push rod in the stand guide is formed, for example, in addition to the storage in the Hebelarmführung. In this case, the stand guide is, for example, arranged transversely to the direction of movement of the press ram. In particular, the stand guide may be formed according to the Hebelarmführung of a shoe and a sliding guide, so that, for example. The already mounted in the Hebelarmführung connection axis is mounted on the further shoe in addition in the further sliding between two positions.

In this case, in particular, a stand guide can be formed on both sides, so that, for example, each connecting axis is mounted in a front and a rear upright element (housing component) by means of a stand guide. For this purpose, for example, in each case a sliding guide can be arranged in the front and the rear upright member for each connection axis, in each of which a arranged at each end of the connecting axis sliding block is movably mounted. The connection axis can thus extend between the stator elements.

According to a development of the invention, an overload protection is arranged. The overload protection protects the press against damage due to excessive pressing pressure. For this purpose, for example, an overload protection in the plunger connections, i. be arranged in the joints between the toggle levers and the press ram.

Such overload protection can be designed in particular as a hydraulic fuse.

However, the overload protection is particularly preferably arranged in the push rod. The arrangement is particularly advantageous because the total force in the region of the push rods is less than at the plunger joints. In addition, only two overload protection must be formed in a conventional arrangement of two push rods.

The overload protection in the region of the push rod can also be designed hydraulically, for example as a hydraulic cushion, which releases hydraulic fluid when the force introduction is too high and, if necessary, automatically stops the press.

The press stroke (the size of the lifting movement of the press ram) can be formed particularly large in relation to the overall height of the forming device by the arrangement of a single drive shaft, which is connected to the two toggle levers. D. h., The forming device is designed to be particularly compact in relation to the size of the lifting movement. Particularly preferably, the first lever arm is also designed cranked, so that a further increase in the press stroke can be achieved with a constant press size.

In addition or instead, a stroke adjustment for changing the height of the press stroke is particularly preferably arranged, whereby particularly high workpieces can be processed. Particularly preferably, the stroke adjustment is designed such that the first lever arm is displaceably mounted on the central bearing axis. The central bearing axes can thus be arranged movable in each case between a lower and an upper position in the first lever arms.

For this purpose, in particular in the first lever arms, for example, an eccentric recess for receiving the central bearing axis and, for example. A lifting device may be arranged which raises or lowers the toggle mechanism with the press ram, so that a displacement of the central bearing axis in the first lever arm between the lower and the upper position takes place. Such a lifting device is, for example, designed as a gear drive.

To increase the working space, i. To achieve the distance between the press ram and the press table, also the ram connections can be made adjustable in the direction of the stroke, whereby the position of the press ram is changeable. As a result, even very high workpieces can be processed at the same height of the press stroke.

Furthermore, the invention will be described in detail with reference to an embodiment. It shows:

1 schematically in a side view of a press drive for a forming device.

1 shows a trained as a servo press forming device 1 with a press frame 2 and a press drive 3 , The forming device 1 is designed to carry out all conventional manufacturing processes, such as. The pressing, bending, drawing, stretching, punching and / or cutting. The press drive 3 has a central drive shaft 4 with an eccentric guide unit 5 on. The drive shaft 4 is coupled to a drive unit (not shown here), which is designed as a torque motor. The drive shaft 4 has an axis of rotation (indicated here by a cross). The direction of the rotation axis corresponds to the drive axis direction.

Next shows 1 a toggle mechanism 6 with two toggle levers 7 , each having a first (upper) lever arm 8th and a second (lower) lever arm 9 exhibit. The first and second lever arm 8th . 9 are each about a swivel joint 10 connected to each other in an articulated manner. The second lever arms 9 are about a likewise formed as hinges plunger connection 11 with a press ram 12 connected. There is every second lever arm 9 via two juxtaposed in the drive axis direction ram connections 11 with the press ram 12 connected so that the toggle mechanism 6 four ram joints 11 with the press ram 12 formed. The press ram 12 is at one in the press frame 2 arranged guide unit (not shown here) movably mounted and can be moved in lifting movement B up and down.

Although not shown here, the first lever arms are 8th from two each in the drive axis direction juxtaposed Hebelarmkörpern 17 designed so that the second lever arm 9 in the area of the first lever arm 8th trained swivel joint 10 centered between the two respective ones, the first lever arm 8th forming, Hebelarmkörpern 17 is arranged.

The two toggles 7 are arranged mirror-symmetrically about the central axis A. The central axis A extends vertically, in the stroke direction of the press ram 12 and cuts the axis of rotation of the central drive shaft 4 , The drive shaft 4 is thus at least partially central between the knee levers 7 , or the toggle 7 are at least partially laterally (right and left) of the drive shaft 4 arranged.

At the eccentric guide unit 5 are two push rods 13 each rotatably mounted with a leading end. With the first end opposite the leading end 14 is every push rod 13 in each case one of the first lever arms 8th movably mounted between two positions. This is at the swivel joint 10 opposite end of the first lever arm 8th one lever arm guide each 15 educated. The lever arm guide 15 consists of one on the push rod 13 arranged sliding block (not shown here), in a in the first lever arm 8th arranged sliding guide 15a is movably mounted between two positions. The shoe is over a connecting axle 16 with the push rod 13 connected.

Both connection axes 16 each extend through the Hebelarmführungen 15 the two (in the drive axis direction) juxtaposed Hebelarmkörper 17 of the first lever arm 8th into a stand guide, so that in addition the storage of the first end 14 the push rod 13 in the stand guide over the connection axes 16 he follows.

Each stand guide also comes with a slide shoe and a sliding guide 18 educated. There are thus four stator guides arranged, each connecting axis 16 each having a sliding shoe at both ends, in the respective sliding guide on the press frame 2 is movably mounted. The stand guide extends transversely to the stroke direction B of the press ram 12 ,

Next shows 1 at each toggle 7 one central bearing axis each 19 in the first lever arm 8th or on the respective Hebelarmkörpern 17 of the first lever arm 8th is arranged. The central bearing axes 19 are each in the first lever arm (in each lever arm body 17 ) rotatably mounted and fixed in the press frame 2 positioned.

To a particularly large stroke of the press ram 12 to reach is the first lever arm 8th formed cranked. To the stroke of the press ram 12 to change, is also a stroke adjustment 20 arranged. The stroke adjustment 20 points in each first lever arm 8th an eccentric recess 21 on, for receiving the central bearing axis 19 is trained. In addition, a lifting device, here a gear drive (not shown here), arranged by means of the toggle mechanism 6 with the press ram 12 in the central axis direction A, ie in height, is adjustable, so that the central bearing axis 19 between the in 1 shown lower and an upper position, where the central bearing axis 19 in the region of the eccentric recess 21 is arranged, is movable.

In operation, the central drive shaft rotates 4 for example, counterclockwise. This is the right push rod 13 raised while the left push rod 13 is lowered. The drive of the toggle 7 thus takes place in opposite directions.

Due to the stand guide and the lever arm guide 15 move the upper ends of the first lever arms 8th from the inner position shown here to the outside, ie away from the central axis A. The movements of the toggle 7 are synchronous and each around the central bearing axis 19 ,

When moving the upper ends of the first lever arms 8th to the outside is the press ram 12 raised. The swivel joints 10 move according to the Hebelarmgeometrie each on the central axis A to the inside. Due to the cranked design of the first lever arms 8th a particularly large ram stroke is achieved.

Once the upper ends of the first lever arms 8th have reached their extreme position, is the press ram 12 completely raised. Upon further rotation of the drive shaft 4 counterclockwise become the upper ends of the lever arms 8th by means of the push rod 13 around the central bearing axis 19 again inward, ie on the central axis A to, moves while the hinges 10 move outward and the press ram 12 is lowered.

Of course, a rotary movement in a clockwise direction or possibly a Pendelhupbewegung is possible.

Furthermore, a hydraulic overload protection is arranged in the push rods, which discharges a hydraulic fluid when exceeding a predetermined limit load and possibly the forming device 1 stops.

LIST OF REFERENCE NUMBERS

1

 reshaping

2

 press housing

3

 press drive

4

 Central drive shaft

5

 Eccentric guide unit

6

 Toggle mechanism

7

 toggle

8th

 First lever arm

9

 Second lever arm

10

 Swivel knee lever

11

 plunger connection

12

 press ram

13

 pushrod

14

 First end push rod

15

 Hebelarmführung

15a

 Sliding guide of the lever arm guide

16

 connecting axis

17

 Hebelarmkörper

18

 Sliding guide of the stand guide

19

 Central bearing axis

20

 stroke

21

 Eccentric recess

22

 press table

A

 central axis

B

 Lifting direction press ram

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012102527 A1 [0002]

Claims (11)

Press drive for a forming device ( 1 ) - a central drive shaft ( 4 ) with an eccentric guide unit ( 5 ), - a toggle mechanism ( 6 ) with two toggle levers ( 7 ), each having a first and a second articulated lever arm ( 8th . 9 ), - wherein the first lever arms ( 8th . 9 ) with the eccentric guide unit ( 5 ) and the second lever arms ( 8th . 9 ) each with at least one plunger connection ( 11 ) with a press ram ( 12 ) are connected. Press drive according to claim 1, characterized in that the second lever arms ( 8th . 9 ) each with at least two plunger connections ( 11 ) with the press ram ( 12 ) are connected. Press drive according to claim 1 or 2, characterized in that the toggle levers ( 7 ) in each case by one in the first lever arm ( 8th ) arranged central bearing axis ( 19 ) are rotatably mounted. Press drive according to one of the preceding claims, characterized in that the first lever arm ( 8th ) and / or the second lever arm ( 9 ) two mutually parallel Hebelarmkörper ( 17 ) having. Press drive according to one of the preceding claims, characterized in that the eccentric guide ( 5 ) a push rod ( 13 ) having a first end in a Hebelarmführung ( 15 ) on the first lever arm ( 8th ) is stored. Press drive according to one of the preceding claims, characterized in that the push rod ( 13 ) with the first end in a stand guide ( 18 ) is stored. Press drive according to one of the preceding claims, characterized in that an overload protection is arranged. Press drive according to one of the preceding claims, characterized in that the overload protection in the push rods ( 13 ) is arranged. Press drive according to one of the preceding claims, characterized in that the first lever arm ( 8th ) is cranked. Press drive according to one of the preceding claims, characterized in that a stroke adjustment ( 20 ) is arranged to change the ram stroke. Press drive according to one of the preceding claims, characterized in that the first lever arm ( 8th ) at the central bearing axis ( 19 ) is slidably mounted.

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